Conventionally, a coronary angiography catheter has been used to supply a radiopaque material (contrast agent) into a coronary artery for imaging the coronary artery.
In addition, treatments of peripheral regions of a patient by use of a catheter or catheters have been widely practiced. One example of such treatments is the percutaneous transluminal coronary angioplasty (PTCA) as a treatment of ischemic cardiopathy based on the use of a therapeutic catheter equipped with an inflatable balloon. In such a treatment, in order to insert the therapeutic catheter into a target blood vessel safely and efficiently and to permit the therapeutic catheter to display a sufficient function in a target site, a guiding catheter is needed. In this case, the guiding catheter provides a backup force so as to relax counteractions arising from the insertion of the therapeutic catheter and to keep the therapeutic catheter in a desired position.
An example of such system is described in U.S. Pat. No. 6,475,195 (hereinafter referred to as Patent Document 1) and U.S. Pat. No. 5,603,704 (hereinafter referred to as Patent Document 2). In this example, a guiding catheter having its distal end engaged in the left coronary ostium makes linear contact with the ascending aorta inner wall opposite to the left coronary ostium, whereby a backup force is generated.
Such a coronary angiography catheter or guiding catheter is normally introduced from a femoral artery by the Seldinger technique, or sheath technique. After the coronary artery is selectively captured by the angiography or guiding catheter, a radiopaque material or a therapeutic catheter such as a PTCA balloon catheter is introduced through the lumen provided inside the angiography or guiding catheter.